Chapter-16-Covalent-Bonding

1Chapter16CovalentBonding2Section16.1TheNatureofCovalentBondingOBJECTIVES:–Useelectrondotstructurestoshowtheformationofsingle,double,andtriplecovalentbonds.3Section16.1TheNatureofCovalentBondingOBJECTIVES:–Describeandgiveexamplesofcoordinatecovalentbonding,resonancestructures,andexceptionstotheoctetrule.4HowdoesH2form?Thenucleirepel++5HowdoesH2form?++ThenucleirepelButtheyareattractedtoelectronsTheysharetheelectrons6CovalentbondsNonmetalsholdontotheirvalenceelectrons.Theycan’tgiveawayelectronstobond.Stillwantnoblegasconfiguration.Getitbysharingvalenceelectronswitheachother.Bysharing,bothatomsgettocounttheelectronstowardanoblegasconfiguration.7CovalentbondingFluorinehassevenvalenceelectronsF8CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenFF9CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons…FF10CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons…FF11CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons…FF12CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons…FF13CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons…FF14CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons……bothendwithfullorbitalsFF15CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons……bothendwithfullorbitalsFF8Valenceelectrons16CovalentbondingFluorinehassevenvalenceelectronsAsecondatomalsohassevenBysharingelectrons……bothendwithfullorbitalsFF8Valenceelectrons17ASingleCovalentBondis...Asharingoftwovalenceelectrons.OnlynonmetalsandHydrogen.Differentfromanionicbondbecausetheyactuallyformmolecules.Twospecificatomsarejoined.Inanionicsolid,youcan’ttellwhichatomtheelectronsmovedfromorto.18HowtoshowhowtheyformedIt’slikeajigsawpuzzle.Youputthepiecestogethertoendupwiththerightformula.Carbonisaspecialexample-canitreallyshare4electrons?–Electronpromotion!Anotherexample-showhowwaterisformedwithcovalentbonds.19WaterHOEachhydrogenhas1valenceelectronEachhydrogenwants1moreTheoxygenhas6valenceelectronsTheoxygenwants2moreTheysharetomakeeachotherhappy20WaterPutthepiecestogetherThefirsthydrogenishappyTheoxygenstillwantsonemoreHO21WaterThesecondhydrogenattachesEveryatomhasfullenergylevelsHOHSample16-1,p.44022MultipleBondsSometimesatomssharemorethanonepairofvalenceelectrons.Adoublebondiswhenatomssharetwopairs(4total)ofelectronsAtriplebondiswhenatomssharethreepairs(6total)ofelectronsTable16.1,p.443-Knowwhichelementsarediatomic(Oxygen?)23CarbondioxideCO2-Carboniscentralatom(moremetallic)Carbonhas4valenceelectronsWants4moreOxygenhas6valenceelectronsWants2moreOC24CarbondioxideAttaching1oxygenleavestheoxygen1short,andthecarbon3shortOC25CarbondioxideAttachingthesecondoxygenleavesbothoxygen1shortandthecarbon2shortOCO26CarbondioxideTheonlysolutionistosharemoreOCO27CarbondioxideTheonlysolutionistosharemoreOCO28CarbondioxideTheonlysolutionistosharemoreOCO29CarbondioxideTheonlysolutionistosharemoreOCO30CarbondioxideTheonlysolutionistosharemoreOCO31CarbondioxideTheonlysolutionistosharemoreOCO32CarbondioxideTheonlysolutionistosharemoreRequirestwodoublebondsEachatomcancountalltheelectronsinthebondOCO33CarbondioxideTheonlysolutionistosharemoreRequirestwodoublebondsEachatomcancountalltheelectronsinthebondOCO8valenceelectrons34CarbondioxideTheonlysolutionistosharemoreRequirestwodoublebondsEachatomcancountalltheelectronsinthebondOCO8valenceelectrons35CarbondioxideTheonlysolutionistosharemoreRequirestwodoublebondsEachatomcancountalltheelectronsinthebondOCO8valenceelectrons36Howtodrawthem?Addupallthevalenceelectrons.Countupthetotalnumberofelectronstomakeallatomshappy.Subtract;thenDivideby2Tellsyouhowmanybonds-drawthem.Fillintherestofthevalenceelectronstofillatomsup.37ExampleNH3,whichisammoniaN-has5valenceelectrons,wants8H-has1(x3)valenceelectron,wants2(x3)NH3has5+3=8NH3wants8+6=14(14-8)/2=3bonds4atomswith3bondsNH38NHHHExamplesDrawinthebondsAll8electronsareaccountedforEverythingisfull39ExampleHCN:CiscentralatomN-has5valenceelectrons,wants8C-has4valenceelectrons,wants8H-has1valenceelectron,wants2HCNhas5+4+1=10HCNwants8+8+2=18(18-10)/2=4bonds3atomswith4bonds-willrequiremultiplebonds-nottoHhowever40HCNPutsinglebondbetweeneachatomNeedtoadd2morebondsMustgobetweenCandNNHC41HCNPutinsinglebondsNeed2morebondsMustgobetweenCandNUses8electrons-2moretoaddtoequalthe10ithasNHC42HCNPutinsinglebondsNeed2morebondsMustgobetweenCandNUses8electrons-2moretoaddMustgoonNtofilloctetNHC43AnotherwayofindicatingbondsOftenusealinetoindicateabondCalledastructuralformulaEachlineis2valenceelectronsHHO=HHO44StructuralExamplesHCNCOHHChas8e-becauseeachlineis2e-sameforNsameforCheresameforO45ACoordinateCovalentBond...Whenoneatomdonatesbothelectronsinacovalentbond.CarbonmonoxideCOOC46CoordinateCovalentBondWhenoneatomdonatesbo